Tested Motor Oil for All-Age Vehicles: Fuel Economy Gain In the quiet hum of an engine, the right motor oil can be the unsung hero of efficiency. Whether your vehicle is a vintage icon or a cutting-edge marvel, the choice of lubricant often determines how smoothly it runs and how far it can go on a tank of fuel. A curated comparison of five standout products reveals a spectrum of innovations tailored to different needs, all aiming to tip the scales toward better fuel economy. Valvoline Restore & Protect Full Synthetic 5W-30, in its 1-quart bottle, blends robust protection with a streamlined formula-ideal for everyday driving where longevity meets performance. Castrol Edge Extended Performance 5W-20, offered in a 5-quart format, steps up with its advanced synthetic composition, designed to minimize friction in newer engines, potentially unlocking subtle but meaningful fuel savings. Meanwhile, Mobil 1 Extended Performance High Mileage 5W-30, packed in a 6-pack of 1-quart bottles, targets aging motors with additives that combat wear and maintain viscosity, ensuring older vehicles don't compromise on efficiency. Quicksilver by Mercury Marine, a 25W-40 specialized oil for marine engines, brings durability to the table, though its niche application may not directly translate to road vehicles. Liqui Moly Motor Oil Saver, in its 300-mL 2-pack, offers a compact, cost-effective solution for drivers seeking targeted improvements, with its formulation promising a balance between cleanliness and energy optimization. While each product has its unique role, the path to fuel economy gain lies in aligning the oil's properties with the engine's demands. Whether you're conserving fuel, protecting aging components, or navigating the specific needs of marine machinery, the right choice isn't just about saving money-it's about saving power.